The present invention relates to an epoxy resin composition. Particularly, it relates to an epoxy resin composition which is excellent in printability, and which has improved properties in crack resistance without detriment to the mechanical strengths such as flexural strength and flexural modulus, and exhibits a low expansion coefficient and a high glass transition point, thus being excellent in moldability including deformation resistance in molding.
An epoxy resin and a composition comprising said resin and an inorganic filler are generally so superior to other thermosetting resins in moldability, adhesion, electrical and mechanical properties, humidity resistance and the like that they have been widely used as, for example, various molding materials, powder coating materials or electrical insulating materials. Particularly, they have recently been noted as the sealing material of semiconductors.
However, many of conventional epoxy resin compositions cause crack in curing to give a molding or coating having a damaged appearance or a defective semiconductor element or device. In order to solve these problems, the inventors of the present invention previously proposed an epoxy resin composition excellent in crack resistance which comprises a curable epoxy resin and a block copolymer comprising an aromatic polymer and an organopolysiloxane (Japanese Patent Laid-Open No. 21417/1983). However, it is still expected to develop an epoxy resin composition which is further improved in crack resistance without detriment to the mechanical strengths such as flexural strength and flexural modulus and exhibits a low expansion coefficient and a high glass transition point, thus being excellent in moldability including deformation resistance in molding.
Further, the above epoxy resin composition containing a block copolymer comprising an aromatic polymer and an organopolysiloxane was problematic in that the surface of a molded article thereof was too poor in printability to print thereon in a making ink.